Mechanical Engineering of Plastic Nose Cones Having Stress-Cracking Tendencies

摘要

Relaxation (applied strain) data are necessary to select a material that can withstand the level of strain in the XM429 design without stress cracking. However, such data are not available for polyphenylene oxide and many other plastics used in ordnance. This prompted a study of the applicability of the more abundant data, namely creep (applied stress), constant strain rate, and bursting pipe (applied pressure) data to this problem; means of using these data in an applied strain problem are described. Bursting pipe data are used to show that low melt index, high-density polyethylene is a material mechanically acceptable for use on the XM429. (Author)